Fix preamble range checks

Change-Id: I0571f4524703566b8840e2b264d868c404f87c80

[email protected],[email protected]
BUG=chrome-os-partner:2910
TEST=make && make runtests

Review URL: http://codereview.chromium.org/6759075
1 file changed